Detection of molecular recognition events has always been an area of primary focus in bioanalytical sciences, as binding between biomolecular objects and other molecular entities in cells governs all cellular functions at the molecular level. The ability to detect interactions between biological molecules is vitally important for the development of new therapies and therapeutic agents. The goal of this proposal is to develop a fundamentally new approach to ultra-sensitive amplified detection of biomolecular recognition events and implement it in low cost bioanalytical microarray chips. The proposed methodology - which is based on self-amplified unmasking of electron-transfer sensitizers - is standardized and universal, i.e. not limited to selected classes of biological molecules and interactions. Once validated using known ligand-receptor pairs, this technology will be applied to a prominent problem in molecular biology: recognition of posttranslational modifications of histone tails. A critically important problem in the chromatin field is to identify new domains capable of reading the histone code. Given a large number of posttranslational modifications in histone tails, derived primarily from methylation or acetylation of their lysine and arginine residues, the search for new reader domains can only be achieved with high throughput combinatorial screening. Heptapeptide libraries containing signature residues of natural histone tails will be synthesized, printed on the amplified detection microarray chips, and screened for binding of domains known to "read" the histone code - chromodomain, bromodomain and the PHD finger. PUBLIC HEALTH RELEVANCE Detection of interactions between biological molecules has always been an area of primary focus in biomedical sciences, as such interactions govern all processes in living organisms. The ability to detect binding between biological molecules is vitally important for the development of new therapies and therapeutic agents. The goal of this proposal is to develop a fundamentally new approach to low cost ultra-sensitive detection methods, which will aid in the discovery of new medicines.